1. Field of the Invention
The present invention relates to a detector for detecting heart depolarizations by sensing electrical signals from a heart.
2. Description of the Prior Art
Reliable detection of spontaneous heart depolarizations is important in the monitoring and treatment of a heart. One known way of detecting heart depolarizations is to record the heart's electrical signals (ECG signals) and to analyze same. In particular, such signals are analyzed to identify the QRS complex, appearing when the ventricles depolarize, which displays very distinctive, fast intrinsic deflection, i.e., rapid changes in the signal. Detection can be identified by analysis of the signal's change (derivative) and duration. This is described in e.g., U.S. Pat. No. 4,417,306.
Power consumption is a problem when detectors are implemented in implantable pacemakers and defibrillators (ICD). An implantable apparatus only has access to the limited amount of energy stored in its battery, and a detector, which should be active most of the time in order to detect heart depolarizations, must not consume too much power.
Space is another problem with implantable devices. Pacemaker and defibrillator designs are becoming increasingly smaller. So components used in such devices must occupy as little space as possible.